If the cut-off ratio in the air standard dual cycle approaches unity, then this lead to which among the following cycles?

Concept:

• The limited pressure cycle is also called as Dual cycle.
• Here the heat addition occurs partly at constant volume and partly at constant pressure.
• This cycle is a closer approximation to the behavior of the actual Otto and Diesel engines because in the actual engines, the combustion process does not occur exactly at constant volume or at constant pressure but rather as in the dual cycle. 

\({\eta _{Dual}} = 1 - \frac{1}{{{r^{\gamma - 1}}}}\left[ {\frac{{{r_p}{ρ ^\gamma } - 1}}{{\left( {{r_p} - 1} \right) + \gamma {r_p}\left( {ρ - 1} \right)}}} \right]\)

Where \({r_p} = \frac{{{P_3}}}{{{P_2}}},ρ = \frac{{{V_4}}}{{{V_3}}},r = \frac{{{V_1}}}{{{V_2}}}\)

rp - pressure ratio, ρ - cut off ratio, r - compression ratio;

• If cut off ratio is one, it will become Otto cycle,
• If pressure ratio is one, it will become diesel cycle